US2626745A - Centrifuge - Google Patents

Description

1953 F. H. FLETCHER, JR 2,626,745

CENTRIFUGE Filed July 13, 1951 5 Sheets-Sheet l FIGJ.

[20' IZI 95 ,N as n21 I I03 E u l f 25 u fi 64 |2l fl lSnventor FRAN K H. FLETCHER JR.

attorney;

Jan.'27, 1953 F. H. FLETCHER, JR

CENTRIFUGE 5 Sheets-Sheet 5 Filed July 13, 1951 VAL ' Snveutor FRANK H.FLETCHER JR.

attorney Jan. 27, 1953 F. H. FLETCHER, JR. 2,626,745

CENTRIFUGE Filed July 13, 1951 5 Sheets-Sheet 4 FRANK H. FLETCHER JR.

(Ittotneg j Patented Jan. 27, 1953 CENTRIFUGE Frank H. Fletcher, J r., Flushing, N. Y., assignor to Ethel K. Haferkamp and Mary Elliott Haferkamp, Oswego, and Virginia H. Fletcher, Flushing, N. Y.

Application July 13, 1951, Serial No. 236,628

13 Claims. 1

This invention relates to centrifuges in which liquid and solid materials are separated by centrifugal action, and in which the charge is continuously fed and the separated materials continuously discharged, and this application is a continuation of my application for United States Patent, Serial No. 756,431, filed June 23, 1947 for Centrifuge, and now abandoned.

More specifically, this invention concerns a centrifuge for liquid and solid material in which centrifuge are employed inner and outer rotatable elements concentrically positioned and diametrically spaced to provide an annular centrifuging space or chamber, and so constructed that one rotatable element serves to drive the other while both revolve at high and substantially similar or different velocities, and the centrifuge being so constructed that, during their rotation, the solids of the material are separated from the l-iquid thereof by centrifugal force, the liquid flowing to a liquid exhaust and the solids to an exhaust or discharge for solids.

Under centrifugal force the liquid of the material entering the centrifuging space or chamber flows toward the end of greater diameter, while the solids are deposited against the inner side of the outer rotatable element and moved longitudinally toward a smaller exhaust or discharge for solids, by means of circumferentially-disposed spaced-apart lifter members on the periphery of an inner or normally slower moving free rotatable element. These members constitute, in no sense, a conventional spiral or screw conveyor.

Such a centrifuge may be used, for example, for separating crystals or other solids from liquids, or for clarifying liquids, or for thickening mixtures of solids and liquids and, particularly, for separating dyes or other fine solids from liquids (the latter operation heretofore usuall requiring bulky filter presses) From the foregoing it will be appreciated that the principal object of this invention is to provide a novel and efficient centrifuge and system for continuous centrifugal separation of mixtures of solids and liquids.

A further object of this inventionis to provide a centrifuge having inner and outer rotatable elements concentrically disposed in diametrically spaced relationship and arranged in such manner that, when driving energy is applied to one of the rotatable elements, the material fed to it and centri-fugally thrown from it, will drive the other element, and by simple and effective means, whereby these elements will maintain any desired difference inrotative speed.

A further object is to provide a centrifuge which may efficiently operate with a high capacity at comparatively high rotative velocities, without danger of jamming or stalling due to overload, while subjecting the material to be'separated to a high centrifugal force and that by removing unwanted solid impurities from crystals that are in solution (or liquid form) or, by removing valuable solids from worthless or unwanted liquids, assures purer crystals and, when desired, a product substantially 99.5 pure and, when desired, a moisture content as low as twotenths of one percent, thus assuring purer crystals, and thus eliminating the necessity of recrystallization to obtain a desired product.

A further object is to provide a centrifuge of high capacity with a centrifuging chamber sufii ciently small as to render economically possible the use of rare, and therefore costly, acid-resistant metals or other suitable material in its construction.

A further object is to provide a novel combination of rotatable centrifuge elements.

A further object is to provide novel rotatable basket and scraper centrifuge elements.

A further object is to provide a novel rotatable centrifuge lifter scraper.

A further object is to provide a novel hydraulic brake mechanism, namely a system and method of operation for one of the rotatable elements in a centrifuge employing a multiple of such elements.

A further object is to provide a system and means for maintaining the temperature in a liquid, under centrifugal processing in a centrifuge, at a suitable value to prevent its crystallization and to assure its free flowing.

A further object is to provide a centrifuge in which no springs are employed, nor is a multiplicity of gears used to provide for the maintenance of various speed differences between the major rotatable elements of the centrifuge, and the entire construction is sturdy and not apt to get out of order.

A further object is to provide a centrifuge which may be operated at speed differences such as 400 R. P. M., with the centrifuge discharging itself every fourth revolution and the friction coefficient reduced substantially one-half over that of conventional screw conveyor type centrifuges.

Other objects and advantages of the invention will be apparent from the following description of the invention, taken in connection with the accompanying drawings, and in whichdrawings:

Figure 1 is a top plan view of the new centrifuge with a prime mover operatively connected therewith.

Figure 2 is an elevational end view of Figure 1.

Figure 3 is a longitudinal vertical section of the new centrifuge.

Figure 4 is a partial top plan view and longitudinal horizontal section of the new centrifuge with piping removed.

Figure 5 i a vertical section taken along the line 5-5 of Figure 3 to disclose portions of brake means.

Figure 6 is a vertical section taken along line 6-6 of Figure 3 and showing portions of a centrifugal pump and its driving mechanism.

Figure '7 is a fragmentary exterior side elevation of the centrifuge housing showing the exterior of the pump of Figure 6.

Figure 8 is a vertical transverse section taken along line 88 of Figure 3, showing portions of a basket assembly forming part of the new centrifuge.

Figure 9 is a view, partly in elevation and partly in vertical section of the basket assembly.

Figure 10 is a face view of the basket with parts broken away to reveal portions of the structure beneath.

Figure 11 is the other face view of the basket assembly.

Figure 12 is one face view of a scraper structure forming part of the new centrifuge.

Figure 13 is a view of the opposite face of this scraper assembly.

Figure 14 is a partly sectional view of the scraper assembly with other parts in elevation.

Figure 15 is a fragmentary development of one of the scraper element surfaces.

Figure 16 is an enlarged fragmentary sectional view showing the relative association of the basket and scraper elements.

Figure 17 is a view partly in vertical section and partly in elevation of a modification of the centrifuge structure and showing portions of a modified brake means.

Figure 18 is a development of the scraper surface in a vertical section, substantially on the line |8--| 8 of Figure 17.

In the drawings, wherein for the purpose of illustration are shown several embodiments of the invention and wherein similar reference characters designate corresponding parts throughout the several views, the letter A designates one form of the new centrifuge and B, another form thereof.

Both of the centrifuges A and B comprise a first or main centrifuge housing E, centrifuging means F, a driven member or shaft G, a scrapercarrying member or shaft H, means K for discharge of solids when separated from the centrifugeable material, a second or brake and pump housing L, brake and pump means M for the form A, a third or pump housing N, pump means P, modification Q of the brake means of the brake and pump means M of the form A for the form B, centrifugal seal R, means S to prevent the centrifuged liquid from crystallizing, and a prime mover T.

Referring mainly to Figs. 3 and 4, the first or main centrifuge housing E may comprise castings, such as an upper housing portion 20 and lower housing portion 2|, suitably removably secured together as by bolt and nut assemblies 22. The walls of the housing define a basket chamber 23 and a centrifuged liquid chamber 24, into the former of which opens a suitable inlet conduit or way 25 for centrifugal material and leading preferably from exteriorly of the housing at the upper end thereof. A centrifuged liquid discharge port 26 is provided adjacent the lower part of the portion 2|, opening from the chamber 24 to a conduit 28 exteriorly of the housing walls, and a moist air discharge port 21 may be provided, as in Fig. 4, through the upper wall of the portion 20 and communicating with the chamber 23.

The driven member G is a shaft and it extends into the housing E and fixedly carries, for rotation therewith, a basket assembly 30, forming a part of the centrifuging means F.

This basket assembly 30, shown particularly in Figs. 9, 10 and 11, includes a hub 3|, to which extends the inner end of the conduit or way 25, and the hub 3| extends about a portion of the member G, being secured thereto, and has a truncated conical portion 32 sloping outwardly to an end wall 33 which may be a disc, with a plurality of spaced-apart distributor vanes 34 mounted thereon. These are preferably curved and extend to the truncated conical portion 32 while their free outer edges are preferably substantially flush with the periphery of the end wall 33. As the rest of the basket assembly rotates, they throw the centrifugeable material against an inclined face 42 of a basket body 4|.

The basket assembly 30 also includes a basket body-carrying member or plate 35, preferably rigid with the vanes 34 and providing, in part, a guideway, at its face portion 36, for the material being projected by the vanes 34. It has, however, other functions as will be explained later. The plate or member 35 is preferably bevelled at its periphery 31 and, inwardly of the periphery, is provided with a plurality of spacedapart liquid and moist air discharge ports 38 arranged a substantially equal distance from the axis of the member 35. The entrance end of each port 38 may be provided with a baffle 39 which, in the example shown, is a disc, carried by the member 35 and spaced slightly from these entrance ends.

To the member 35 is secured, in any approved way, as by bolt and nut assemblies 40, a basket casing or body 4| having open ends and with side walls sloping inwardly away from the ports 38 at locations outwardly of the ports 38. The inner, sloping face 42 of the body 4| is preferably smooth, but the outer face is provided with spaced-apart, outwardly-extending ribs or flanges 43 and 44 which ride in suitable grooves or recesses in the walls of the housing E, as is clear in Figs. 3 or 16. Liquid, separated from the centrifugeable material, travels along the smooth sloping face 42 toward and out of the ports 38.

A further portion of the basket assembly 30 comprises blower vanes 44, shown especially in Fig. 11 and also carried and projecting from a face of the member 35 opposite to that to which the basket body 4| is secured. It will be noted, as in Fig. 11, that the liquid discharge ports 38 are at the inner or axis ends of the vanes 44. These vanes 44 and the ports are provided, in part, in order to eliminate the possibility of most air coming into contact with the dry separated solids, for the member 35, when rotating, causes the vanes to draw the moist air from the basket body 4| and centrifuge chamber 6| into the chambers 23 and 24. This air ordinarily discharges from the port 21, shown in Fig. 4, which is in communication with the chamber 23.

The scraper assembly 50 of the centrifuge means F is shown particularly in Figs. 12 to 15 see-e745 l sivean i l s a rotatab e .b dy 9 fi e-- ment5l provided witha plurality efspaced-apart diffuser vanes 52 and spaced apart scraperlifter member assemblies,such as the assemblies 53 and 54, andthe element 5| is fi xedlymounted upon the scraper-carrying member or shaft H to rotatetherewith. Since the axes of rotation of the two members G and H (although these members are-separatedfor independent rotation) are substantially aligned, the axes of rotation of the assemblies and are also; aligned.

Preferably, most of the assembly '50 fits into the basket body 4 l, as in Fig, 3, and is truncatedconical, less in thickness than the body 41, with an outer. preferably smooth face 55and the diffuser vanes 52 .fan out from its larger end, whereby their outerfaces formcontinuations of the face 55, as in Big. 13, but their inner faces are raised from the inner face 56 of the rotatable element to form the curved vane bodies as in Fig. 14. e i

It is preferred to form the scraper-lifter member assemblies 53 with scraper-lifter member 5"! staggered with reference to the scraper-lifter members 59 of the assemblies 54, as is clear in Fig. 15. A suitable number (as two, in Fig. 15) of members 51 are rigidly mounted upon a suitable plate 58 which may be rigidly mounted, in turn, upon the rotatable element 5 l,.as by screws, to extend oyer the outer face 55 with portions of the plates ,58 overlapping portions of the inner face 56. In the example shown, there are two sets of assemblies 53 disposed substantially 180 apart. Each of the assemblies 54 may comprise three spaced-apart scraper-lifter members, 59 rigidly mounted upon a plate 60 which is, in turn, rigidly mounted upon therotatable element 5!, as by screws, to extend over the outer face 55 with portions of the plates 60 overlapping portions of the inner face 56. In the example shown, there are two sets of assemblies spaced substantially 180 apart and spaced substantially 90 from the assemblies 53. In Fig. 14 it will be seenv how the outer edges of the members 59 are associated with the inner face 42 of the basket body 4|. The outer edges of the members 51 are associated therewith in alike manner. A feature is not only to stagger the relative positions of the members 51 with respect to the members 59 but to stagger the relative positions of the members 5'! and 59 of one of their respective assemblies with the relative positions of these members of the otherrespective assemblies, as may be observed in Fig. 15. By this arrangement', not only does athoroughscraping action ensue but there is a necessary lifting of the solid material accomplished. The assemblies 30 and 5f provide a centrifuge chamber Bl, best shown in Fig. 16.

I have provided special means K for the discharge of the solids separated from the centrifuged material. This meanscomprises a housingportion 62 best shown in Fig. 3, and vibrator means 83 associated therewith to vibrate the portion St. The portion 6| preferably comprises an upper preferably sloping wall 64, substantially vertical end wall 65 and facing end wall 66 with side walls til joining the walls 64, 65 and 66 and all defining, with adjacent parts of the walls of the housing portions 20 and 2 l a discharge way 68. The material of at leastthe wall 65 is flexible and preferably, soft rubber, and the walls 64, 66 and 61 are,,preferably, flexible as well. In t. the p ti n 8 s pref rab v, ainiesre seamless structure, having a suitable opening 69 for a bearing Sleeve 2 su roundin a po io o the shaft H, and an orifice H opening to the'discharge ends of the basket assembly 30 and scraper assembly 50. The portion 62 may be mounted , uponthe housing portions 20 and 2|, as by mean of screws 72. The vibrator means 63' may be any conventional vibrator adapted to vibrate or shake thehousing portion El and it ma b ounte u o h Wall 64- No only at e ibr ons p nt h s ns b t y tend to set up slight air currents so that any moist airwithin the discharge way 68 will not pocket but will tend to be more readily removed through the port 38 as described.

The s ndgc gbfak a mp u n L may comprise an upper housing portion 15 and lower housing portion 16, dgl'gflqhably secured together as by means, 1L comprising nut and bolt assemblies. The housing L contains a'suitable' opening for the shaft H with the latter mounted therein on anti-friction bearings 78 and I9, and afiuid discharge port 86 adjacent its lower end and'from which port Bil a discharge conduit 3| is provided. Brake and pump means M as shown in Figs. 3, 5 and 6, is an oil type actuated brake and includes a brake drum or rotor fixedly mounted upon the shaft Hand is provided with, preferably, two banks of vanes 86 which may be formed by cutting into the periphery of the drum 85, and extending a short distance alongthe side walls. These vanes 86 are preferablyslightly inclined to the axisofrotation of the drum 85 as may be appreciated from Fig. 4, and are interposed in the path of travelof suitable hydraulic liquid (as oil) flowing through a passageway 81 extending from exteriorly of the housing L, as shown in Fig. 5, and, having an outlet 98, there being aminimum of clearance between the outer end of the outlet 88 andthe vanes 86. I V H Mountedfixedly upon the shaft His a worm 89 meshingwith a worm wheel 90 fixedly mounted on a shaft 3| extending transversely of the chamber of the housing L and disposed within a sleeve 92, with the shaft 9| provided with a pump impeller 92 fixedly mounted thereon and contained within a suction head 930i a centrifugal pump mounted upon the housing portion 16 as may be seen in Fig. '7. The suction head has an intake port 94 for suction fluid and a discharge port 94 for the discharge thereof. Referring now to the driven or basket-carrying, shaft G, it is suitably supported in a third or pump. housing N an extends r u nd utwardly of the housing N at both ends thereof. One part of the shaft G extends into the housing E as stated andthe other end is provided with any'djesirable means, such as the coupling 95 to deta'chably secure it to the drive shaft l2! of a suitable prime mover 'I.

The third or gear and pump housingN is provided for the pumpmeans P and preferably contains antifriction bearings Ifilland ill! for the shaftI-l, anda dischargeport IE2 leading tofa conduit is exteriorly of the housing N. The part of this shaft H within the housing N fixedly mounts a worm Hi l of the pump'means Pwhich 7 Other than as next described, both centrifuges A and B are substantially alike.

The means Q eliminates the drum 85 and substitutes an embodiment of the Pelton waterwheel, employing a braking wheel I05 and an actuating wheel I06 both fixedly secured to the shaft I-I. Each wheel carries cups I01 or I08 respectively, with the cups I'I of the wheel I facing in a direction opposite to that of the cups I08 of the wheel I06. Between and spaced from each wheel and spaced from the outer faces of each of these wheels are suitable walls I09 providing barriers to prevent fluid interference between the wheels. This fluid may be air or water under pressure, or steam, and the fluid is fed through a nozzle IIO to impinge upon the inner surfaces of the cups I 01 of the wheel I05 and applies a retarding or braking force upon the shaft H in order to maintain a selected speed differential between the speeds of rotation of the basket assembly 30 and scraper assembly 50. A like fluid is fed through the nozzle I I I to impinge upon the inner surfaces of the cups I08 of the wheel I06 inorder to bring the rotation of the scraper assembly 50 up to that of the pre-set speed of the basket assembly 30.

I have discovered that it is very desirable to provide an effective centrifugal water seal R at the location indicated by the seal R in Fig. 3. Such a seal is described in my United States Patent No. 2,505,391, dated April 25, 1950 for a seal for centrifugal machines.

Means S is provided to prevent the centrifuged liquid from crystallizing or freezing within or around the ports 33, because of the rapid evaporation of the liquid at the high velocities of rotation of the basket assembly 30. This means is, preferably, a suitable fluid, as steam or hot gas, discharged toward the discharge ends of the ports 38 as they pass, one after another, as the basket assembly rotates, adjacent a discharge nozzle I I 5 of a tube or conduit II6 leading from exteriorly of the centrifuge and operatively connected with a source (not shown) of suitable fluid under pressure.

The shaft G is operatively connected, as at the coupling 95, with a coupling I20 of a drive shaft I2 I of a suitable prime mover T, such as an electric motor.

The conduits 3| and I 03 lead to any suitable container (not shown) for discharged fluid since it may be re-employed.

In order to provide for effective operation of the pump and brake means M and P as well as, in the modification B, of the brake means Q, I prefer to employ the Automatic Control Mechanism for Brakes and the Like described in my application for United States Letters Patent, Serial No. 236,627, filed July 13, 1951, concurrently herewith. Briefly, this mechanism includes a conduit I20 leading to the two laterals I2I for the ports 04 of the two suction heads 93. This conduit leads from one discharge port of a diaphragm controlled balanced valve structure forming a part of this control mechanism, while a conduit I22 leads from the opposite discharge port of this valve structure to the passageway 81 in the housing L and associated with the brake means M.

From the head 93 connected with the housing N, a fluid discharge conduit I23 leads from the discharge port 94' of the suction head 93 of the means P of housing N, to like sides of two diaphragm-divided chambers of the control mechanism.

From the other head 93. a fluid-discharge conduit I24 leads from its discharge port 94 to the two opposite like sides of the two diaphragmdivided chambers of the control mechanism.

As for the conduits to the nozzles I10 and III, a conduit I25 may extend to be operatively connected with one port of the balanced valve of my application for Automatic Control Mechanism for Brakes and the Like, referred to previously, while a conduit I26 may extend to be operatively connected with the other port of this valve.

As shown in Figure 3, the material to be centrifuged or treated is supplied to the basket chamber 23 through the inlet 25 and from thence travels longitudinally along the truncated conical portion 32 of the basket hub 3| and to the path of the basket distributor vanes 34. The vanes 34 throw the material against the inclined face and the diffuser vanes 52 of the rotatable scraper element 5I, rotating at substantially the same speed as that of the basket assembly 30. The element 5!, in the absence of speed control or speed regulating mechanism, rotates with and at substantially the same speed as the basket assembly 30 by virtue of the frictional connection produced solely by the unseparated material being thrown from the distributor vanes 34 against the inclined face of the rotatable element 5I. The material is then deposited against the inner wall of the basket body II. The existing centrifugal force causes the separated liquor to flow upwardly along the inner sloping smooth face 42 to the larger-diameter discharge end of the basket body 4| and thence through the liquor discharge ports 38 into the chamber 24, and finally out through the port 26.

The substantially dry centrifuged solid material is discharged from the smaller-diametered discharge end of the basket body 4I. Due to the high velocity of rotation of the basket assembly 30, the separated solid material is thrown with great force into the discharge way 68 of the housing portion 62, generally if this portion were not as herein provided the dry material would cake upon the walls thereof. However, the flexible walls 64 to 61 when caused to vibrate prevents this caking.

In order to secure relatively different speeds of the basket assembly 30 and the scraper assembly 50, which will cause the rotatable element 5| to rotate at a speed around the inner wall of the basket body 42 substantially equal to the difference between the speed of the body 42 and that of the scraper element 5! and thus effect continuous discharge of the solids which may adhere to the inner face 42 of the basket body II by the scraping action of the scraper members 51 and 59, the means M is provided, constructed and arranged to apply a braking load on the scraper-carrying shaft H sufficient to retard the velocity of the scraper assembly 50 with respect to that of the basket assembly 30 by such amount as is predetermined.

The regulated potential pressures are generated by means of the driven or basket-carrying shaft G and the scraper-carrying shaft H, balanced against each other and separated by a common diaphragm of the said automatic control mechanism for brakes referred to above, which diaphragm is operatively connected with the valve piston of the balanced valve structure of that mechanism, which piston controls the flow of actuating fluid supplied to the hydraulic brake drum through conduit I 22. The brake is so constructed that the greater the volume of fluid impinging upon the drum vanes 86, the greater will be'the braking force, resulting in a relatively lower speed of the scraper assembly 50'. Thus, there maybe maintained any predetermined speed difference between'the scraper assemblytfl and thebasket-assembl'y 39.

The two potential pressures are preferably developed by means of the two means M and P. A pressure is supplied by each means M and P by means of the two pump structures disclosed by way of the conduits I23 and E24 to its designated side of the valve-regulating diaphragm of the control mechanism-in direct proportion to the speed of its particular drive shaft. Thus, one pump 32, through its discharge conduit I23 supplies a constant pressure chamber of the control means by means of said control mechanism, while" the other pumpthrough its discharge conduit !24 supplies a variable pressur chamber of the control mechanism.

When the basket assembly 30 is rotated at a high speed; its distributor vanes 34 throw the liquid (until aspeed diiference is accomplished) against the inclined face of the scraper element 5i and then, in turn, throw the liquid into the chamber 24. The scraper element 5! is thereby caused to rotateat substantially the same high speed as the basket assembly 39. Consequently, the discharge output of the pump of the means P will be the same as that of the pump of the means M and, as equal pressure will then be supplied to the constant pressure chamber and variable pressure chamber and the diaphragm ther'ebetween will remain stationary at its normal or centered position, and the valve piston of the balanced-valve structure will be so positioned that no liquid will pass through the valve, thus the brake'on the scraper carrying shaft H will be unaffected. 7

Should a'sudden overload of solid material be forced into the'space between the basket body 4| and rotatable element 5| the tendency of the element 5| would be to rotate at the same speed as that of the basket body 4| due to the effective resistance of the accumulating solid material in this space. In this event the scraper assembly speed and, consequently, the speed of the scraper-carrying shaft pump H, and the pressure in the variable pressure chamber, are both increased and diaphragm at one side of this chamber will move to open the balanced valve and thus braking pressure is applied sufficient to maintain the required constant relative speed differential between the scraper and basket assemblies.

Due to the staggered lifter vanes or members construction less than l0% of the total centrifuged mass is acted upon at any one time. Also, due to the staggered lifter vanes construction, it is possible to increase the speed difference. A higher speed difference and staggered vanes construction means a smaller and shorter basket may be provided. This, in'turn, means a decrease in mass in the basket. The liquor can escape freely to the larger diameter of the basket.

The relatively small exposed surface of the basket and scraper assemblies 3% and 5B respec tively, including their unitary parts m ne basket and centrifugal chambers, makes possible the employment of rare metals or other material for plating, coating, lining, or construction of the parts which may be exposed to destructive chemicals in connection with which this centrifuge may be used. This feature is of considerableeconomical importance when considered along with the more bulky types of machines which it replaces. I Various changes may be madeto the torms of 'the invention herein"shown and described without departing from the spirit of the inve'n tion or scope of the claims.

What is claimed is: r l 1. A centrifuge forliquid-solids material, including two substantially axially-"aligned rotat ing members disposed out of contact one with the other, a centrifuge basket assembly fixedly mounted upon one o'f said members for rotation therewith and provided-with ahollow basketlbody having a truncated tomcat inner eriphery, a scraper assembly disposed within said basket assembly and fixedly mounted upon the other of saidmembers for rotation therewith and includ inga rotatable element with a truncated conical outer periphery, disposed with said'periphe r'ies in spaced-apart fa'cing relationship, the space between said peripheries providing a centrifuge chamber and the distance between said peripheries being such that said material thrown off from said basket body will strike and rotate said rotatable element, and means, assisted by centrifu'gal force, carried by said element and basket assembly to cause the liquid of said material to flow along said chamber'in one spiral direction to the larger mouth of'said chamber and cause the solids ofsaid material to move along s id chamber in the opposite s iral directionto the sma ler mouth of' said chamber. Y 2. A centrifuge for li uid-solids material, in cluding two substantially axially-alfined'rotating members disposed out of contact? one. with the other, acentrifu e basket assembly fixedly mounted upon one of said members for rotation therewith andprovided with a hollow body having a truncated conical inner periphery, a scraper assembly disposed within said basket assembly and fixedly mounted upon the'other of said members for rotation therewith and including a rotatable element'with a truncated'conical' outer peri hery, dis osed with said peripheries in spaced-apart facing relationship, said centrifuge having a centr fu e chamber in" the space between said peripheries, means to cause said material to impact and rotate said rotatable element, and means, assisted by centrifugal force, carried by said element and'bask'et assembly to cause the liquid of said material to flow along said chamber in one spiral direction'tothe larger mouth of said chamber and cause the 'solids'of said material to move'along said chamber in the onpositespiral directionto the smaller mouth of said chamber, including a plurality of wholly spaced-apart, substantially straight, scraperlifter members carried by said rotatable" element and projecting from said outer periphery.

3. A centrifuge for'liduid-solids material, including two substantially arially-aligned rotating members disposed out of contact one with the other, a centrifuge basket assembly fixedly mounted uponone of said members for rotation therewith 4 and provided with hollow basket body having-a truncated conicalinner periphery,

a scraper assembly disposed within said basket assembly and fixedly mounted upon'the otherof said members for rotation therewith and mama ing a rotatable'elem'ent with a truncated conical outer periphery, said centrifuge having a centrifuge'chamber in the 'spacebetween said peripheries, means to cause said material to impact and rotate said rotatable element, and means assisted by centrifugal force, carried by said element and basket assembly to cause the liquid of said material to flow along said chamber in one spiral direction to the larger mouth of said chamber and cause the solids of said material to move along said chamber in the opposite spiral direction to the smaller mouth of said chamber, including a plurality of wholly spaced-apart substantially straight scraper-lifter members carried by said rotatable element and projecting from said outer periphery in staggered relationship one group with respect to another.

4. A centrifuge for liquid-solids material, including two substantially axially-aligned rotating members disposed out of contact one with the other, a centrifuge basket assembly fixedly mounted upon one of said members for rotation therewith and provided with a hollow basket body having a truncated conical inner periphery, a scraper assembly disposed within said basket assembly and fixedly mounted upon the other of said members for rotation therewith and including a rotatable element with a truncated conical outer periphery, disposed with said peripheries in spaced-apart facing relationship, said centrifuge having a centrifuge chamber in the space between said peripheries, means to cause said material to impact and rotate said rotatable element, and means assisted by centrifugal force, carried by said element and basket assembly to cause the liquid of said material to flow along said chamber in one spiral direction to the larger mouth of said chamber and cause the solids of said material to move along said chamber in the opposite spiral direction to the smaller mouth of said chamber, including a plurality of wholly spacedapart groups of wholly spaced-apart substantially straight scraper-lifter members carried by said rotatable element and projecting from said outer periphery in staggered relationship one group with respect to another group.

5. A centrifuge for liquid-solids material, in eluding two substantially axially-aligned rotating members disposed out of contact one with the other, a centrifuge basket assembly fixedly mounted upon one of said members for rotation therewith and provided with a hollow basket body having a truncated conical inner periphery, a scraper assembly disposed within said basket assembly and fixedly mounted upon the other of said members for rotation therewith and including a rotatable element with a truncated conical outer periphery, disposed with said peripheries in spaced-apart facing relationship, said centrifuge having a centrifuge chamber in the space between said peripheries, means to cause said material to impact and rotate said rotatable element, and means assisted by centrifugal force, carried by said element and basket assembly to cause the liquid of said material to flow along said chamber in one spiral direction to the larger mouth of said chamber and cause the solids of said material to move along the chamber in the opposite direction to the smaller mouth of said chamber, including a plurality of wholly spacedapart groups of wholly spaced-apart elongated scraper-lifter members carried by said rotatable element and projecting from said outer periphery in staggered relationship one group with respect to another group, the longitudinal and transverse center of each member of a group being upon an imaginary straight line common to all the members of a group.

6. A centrifuge for liquid-solids material, including two substantially axially-aligned rotating members disposed out of contact one with the other, a centrifuge basket assembly fixedly mounted upon one of said members for rotation therewith and provided with a hollow basket body having a truncated conical inner periphery, a scraper assembly disposed within said basket assembly and fixedly mounted upon the other of said members for rotation therewith and including a rotatable element with a truncated conical outer periphery, disposed with said peri in spaced-apart facing relationship, said centrifuge having a centrifuge chamber in between said peripheries, means to cause said material to impact and rotate said rotatable element, and means assisted by centrifugal force, carried by said element and basket assembly to cause the liquid of said material to flow along said chamber in one spiral direction to the larger mouth of said chamber and cause the solids of said material to move along said chamber in the 0pposite spiral direction to the smaller mouth of said chamber, said basket assembly also including a portion provided with a plurality of circumferentially spaced-apart discharge ports facing said larger mouth.

'7. A centrifuge for liquid-solids material, including two substantially axially-aligned rotating members disposed out of contact one with the other, a centrifuge basket assembly fixedly mounted upon one of said members for rotation therewith and provided with a hollow basket body having a truncated conical inner periphery, a scraper assembly disposed within said basket assembly and fixedly mounted upon the other of said members for rotation therewith and including a rotatable element with a truncated conical outer periphery, disposed with said peripheries in spaced-apart facing relationship, said centrifuge having a centrifuge chamber in the space between said peripheries, means to cause said material to impact and rotate said rotatable element, and means, assisted by centrifugal force, carried by said element and basket assembly to cause the liquid of said material to flow along said chamber in one spiral direction of the larger mouth of said chamber and cause the solids of said material to move along said chamber in the opposite spiral direction to the smaller mouth of said chamber, said basket assembly also including a portion provided with a plurality of circumferentially spaced-apart liquid discharge ports facing said larger mouth and a plurality of blower vanes disposed at the outlets of some of said ports.

8. A centrifuge for liquid-solids material, including two substantially axially-aligned rotating members disposed out of contact one with the other, a centrifuge basket assembly fixedly mounted upon one of said members for rotation therewith and provided with a hollow basket body having a truncated conical inner periphery, a scraper assembly disposed within said basket assembly and fixedly mounted upon the other of said members for rotation therewith and including a rotatable element with a truncated conical outer periphery, disposed with said peripheries in spaced-apart facing relationship, said centrifuge having a centrifuging chamber in the space between said peripheries, means to cause said material to impact and rotate said rotatable element, and means assisted by centrifugal force, carried by said element and basket assembly to cause the liquid of said material to flow along said chamber in one spiral direction to the larger mouth of said chamber and cause the solids of said material to move along said chamber in the opposite spiral direction to the smaller mouth of said chamber, said basket assembly also including a portion provided with a plurality of circumferentially spaced-apart liquid dis-charge ports facing said larger mouth and a plurality of radially-disposed blower vanes disposed at the outlets of some of said ports.

9. A centrifuge for liquid solids material, including two substantially axially-aligned rotating members disposed out of contact one with the other, a centrifuge basket assembly fixedly mounted upon one of said members for rotation therewith and provided with a hollow basket body having a truncated conical inner periphery, a scraper assembly fixedly mounted upon the other of said members for rotation therewith and including a rotatable element with a truncated conical outer periphery, disposed with said peripheries in spaced-apart facing relationship, said centrifuge having a centrifuging chamber in the space between said peripheries, means to cause said material to impact and rotate said rotatable element, and means, assisted by centrifugal force, carried by said element and basket assembly to cause the liquid of said material to flow along said chamber in one spiral direction to the larger mouth of said chamber and cause the solids of said material to move along said chamber in the opposite spiral direction to the smaller mouth of said chamber, including a plurality of rotating distributor vanes, said basket assembly also including a plate provided with a plurality of circumferentially spaced-apart liquid discharge ports facing said larger mouth, and said rotatable element also includes a plurality of spaced-apart diffuser vanes flaring outwardly from the larger end of said rotatable element and with their free ends facing and closely adjacent the inlets of said ports and encircling the rotating distributor vanes.

19. A centrifuge for liquid-solids material, ineluding a housing having walls including a partial end wall, two separated and substantially axially aligned rotating members carried by said housing with their axes of rotation substantially aligned, a centrifuged basket assembly fixedly mounted upon one of said members for rotation therewith and provided with a hollow basket body having a truncated conical inner periphery, a portion provided with opposite faces and a plurality of spaced-apart liquid discharge ports facing said larger mouth said portion covering the larger end of said hollow basket body with said ports opening into the hollow thereof, a scraper assembly disposed within said basket assembly and fixedly mounted upon the other of said members for rotation therewith and including a rotatable element with a truncated conical outer periphery, disposed with said peripheries in spaced-apart facing relationship, and defining a centrifuge chamber, means to cause said material to impact and rotate said rotatable element, including distributor vanes carried by said portion of said basket body and diffuser vanes carried by said rotatableelement encircling the rotating distributor vanes and disposed in the path of travel of centrifugally thrown material from said distributor vanes, said material being thrown off from said basket body, means carried by said element and basket assembly to cause the liquid of said material to flow along said chamber in one spiral direction to the larger mouth of said chamber and cause the solids of said material to move along said chamber in the opposite spiral direction to the smaller mouth of said chamber, a vibratory housing covering and spaced from said partial end wall, said vibratory housing and parend wall providing a centrifuged solids maal passageway opening to said smaller mouth,

means to vibrate said vibratory housing.

ll. A centrifuge according to claim 10 characterized in that said vibratory housing includes a Wall of soft rubber facing said smaller mouth.

12. A centrifuge according to claim 3 characterized in that said basket assembly also includes a substantially vertically-disposed portion provided with a plurality of circumferentially spaced-apart liquid discharge ports with their entrance mouths facing said larger end, and said centrifuge also includes hot fluid means to pre vent the freezing of liquid in said ports, including the wall of a hot fluid discharge mouth adjacent the eXit mouths of said ports as said portion positions said ports, one after another, adjacent said hot fluid discharge mouth and a conduit between. said source and said mouth.

13. A centrifuge according to claim 3 characterized in that said basket assembly also includes a substantially vertically-disposed portion provided with a plurality of circumferentially spaced-apart liquid discharge ports with their entrance mouths facing said larger end, and said centrifuge also includes means to prevent the freezing of liquid in said ports, including the wall of a hot fiuid discharge mouth adjacent the exit mouths of said ports as said portion moves said ports, one after another, adjacent said hot fluid discharge mouth, said hot fluid discharge mouth being adjacent the lowermost-positioned of said ports.

FRANK H. FLETCHER, J R.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 945,592 Phillips Jan. 4, 1910 1,124,807 Robertson Jan. 12, 1915 FOREIGN PATENTS Number Country Date 1,218 Great Britain Nov. 12, 1898 17,456 Sweden Oct. 29, 1902

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